• Title/Summary/Keyword: Scale constant

검색결과 892건 처리시간 0.028초

초소형 정적 연소실의 열손실 분석 (ANALYSIS OF HEAT LOSS IN A CONSTANT VOLUME MICRO COMBUSTOR)

  • 나한비;이대훈;권세진
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
    • /
    • pp.231-235
    • /
    • 2002
  • A theoretical and experimental study on the combustion process in a constant volume micro combustor is described. Unlike in a macro scale constant volume combustor, the heat loss to the wall plays a major role in flame propagation in a micro micro combustor. In order to analyze the effect of heat loss on combustion phenomena, pressure transition from ignition was measured. A number of cylindrical micro combustors with different diameter and depth were used for experiment to study the effect of length scales and shape factor. The diameter of combustor ranged from 7.5mm to 22.5 mm and the height of cylinder was from 1mm to 4mm. Initial pressure was also varied for the experiment. The diagnostic methods were severely limited due to the size of the apparatus and uncertainties of certain quantities to be measured in a small-scale environment. An analytical method to derive physical quantities that are essential for performance prediction from the pressure measurements is described.

  • PDF

나노 구조 MOSFET의 문턱전압 변화를 최소화하기 위한 스케일링 이론 (Scaling theory to minimize the roll-off of threshold voltage for nano scale MOSFET)

  • 김영동;김재홍;정학기
    • 한국정보통신학회:학술대회논문집
    • /
    • 한국해양정보통신학회 2002년도 추계종합학술대회
    • /
    • pp.494-497
    • /
    • 2002
  • 본 논문에서는 halo doping profile을 갖는 나노구조 LDD MOSFET의 문턱전압에 대한 시뮬레이션 결과를 나타내었다. 소자 크기는 generalized scaling을 사용하여 100nm에서 40nm까지 스케일링하였다. Van Dort Quantum Correction Model(QM)을 사용하여 정전계 스케일링과 정전압 스케일링에 대한 문턱 전압과 각각의 게이트 oxide 두께에 대한 direct tunneling 전류를 조사하였다. 게이트 길이가 감소할 때 정전계 스케일링에서는 문턱전압이 감소하고, 정전압 스케일링에서는 문턱전압이 증가하는 것을 알 수 있었고, 게이트 oxide두께가 감소할 때 direct tunneling 전류는 증가함을 알 수 있었다. 감소하는 채널 길이를 갖는 MOSFET 문턱전압에 대한 roll-off 특성을 최소화하기 위해 generalized scaling에서 $\alpha$값은 1에 가깝게 되는 것을 볼 수 있었다.

  • PDF

Three level constant stress accelerated life tests for Weibull distribution

  • Moon, Gyoung Ae
    • Journal of the Korean Data and Information Science Society
    • /
    • 제26권1호
    • /
    • pp.281-288
    • /
    • 2015
  • In this paper, the maximum likelihood estimators and confidence intervals for parameters of Weibull distribution are derived under three level constant stress accelerated life tests and the assumption that a log quadratic relationship exits between stress and the scale parameter ${\theta}$. The compound linear plan proposed by Kim (2006) is used to allocate the test units at each stress level, which performed nearly as good as the optimum quadratic plan and had the advantage of simplicity. Some simulation studies are given.

AN AUTOMATED TEST FACILITY FOR EVALUATING FRICTION MATERIAL FOR AUROMOTINE-TYPE DISC BRAKES

  • Hancke, G.P.;Zietsman, R.E.
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
    • /
    • pp.776-780
    • /
    • 1989
  • A constant torque dynamometer with associated instrumentation and control functions for the development of friction materials for automotive-type disc brakes, has been developed. Full scale disc pads are subject to a series of intermittent brake applications at a constant rotational speed of the brake disc and constant braking power. This paper gives a description of the dynamometer and an example of results obtained.

  • PDF

체지방측정이 가능한 전자식 체중계의 개발 (Development of body-fat measurable electronic scale.)

  • 최병상;김일환;박찬원
    • 산업기술연구
    • /
    • 제26권B호
    • /
    • pp.243-248
    • /
    • 2006
  • The purpose of this study is to design a body-fat measurable electronic scale which can measure body impedance and weight. The hardware configuration of this system for the body-fat measurement includes a sinewave constant current generator, a analog switch circuit and a microprocessor with peripheral interface as well as electronic scale circuit. And the dedicated software is also designed for calculating body fat and body composition analysis from the result of the measurement.

  • PDF

길이 스케일이 관여된 층류 화염의 연소 속도 이해 (Understanding of Laminar Burning Velocity within a Length Scale Domain)

  • 정용진;최용운;김남일
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
    • /
    • pp.77-78
    • /
    • 2015
  • Laminar burning velocities have been predicted by constant volume combustion chamber, counter flow burner and others. In this study, the measured flame propagation velocities in an assembled annular stepwise diverging tube were plotted with respect to equivalence ratio, length scale, and velocity scale. Three dimensional approach to understand the flame propagation velocity including laminar burning velocity is investigated, and the surface provides the correlation among quenching distance, propagation velocity, and equivalence ratio.

  • PDF

ATM 접속노드에서 셀 손실율과 버퍼용량 및 지연시간의 상관관계 분석 (Performance Relation Analysis of CLR, Buffer Capacity and Delay Time in the ATM Access Node)

  • 이하철;이병섭
    • 한국통신학회논문지
    • /
    • 제27권10C호
    • /
    • pp.945-950
    • /
    • 2002
  • 본 논문에서는 유선 및 무선환경에 상관없이 ATM(Asynchronous Transfer Mode) 접속망의 주요구성 요소인 ATM 접속노드의 셀 손실율, 버퍼용량 및 지연시간간의 상관관계를 제시함으로서 ATM접속망 설계를 위한 기본적인 기술적 사항을 분석하였다. 이를위해 ATM 접속노드의 트래픽 성능평가를 위한 트래픽 모델을 ATM cell-scale queueing, burst-scale queueing 레벨로 구분하여 설명하였고 CBR(Constant Bit Rate), 랜덤 및 VBR(Variable Bit Rate) 트래픽 형태별 모델적용을 검토하였다. 결국 유선 또는 무선방식으로 ATM 서비스를 제공하기 위한 ATM접속노드 설계시 서비스별 QoS(Quality of Service)를 만족시키기 위한 셀 손실율, 버퍼용량 및 지연시간간의 상관관계를 정량적으로 분석하였다.

마이크로 코일 스프링의 스프링 상수 평가 (Evaluation of the Spring Constant of a Micro Coil Spring)

  • 이종길;전병희
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2001년도 추계학술대회 논문집
    • /
    • pp.255-259
    • /
    • 2001
  • The spring constant of a micro coil spring was measured by uniaxial tensile test. The inner diameter of it is $35{\mu}m$ and the pitch size is about $23{\mu}m$. A suing constant measurement system was developed. It consists of control units, load cell units, linear stages and several specially designed jigs and fixtures. Load and displacement are measured using a commercial load cell of 1000g capacity and a magnetic scale of $0.5{\mu}m$ resolution. In this study, a method to measure the spring constant of micro coil spring is presented and the relationship between misalignment of specimen and measurement error is discussed.

  • PDF

시간지연이 있는 대규모 이산시간 시스템의 상태궤환 최적제어 (State feedback optimal control of large-scale discrete-time systems with time-delays)

  • 김경연;전기준
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
    • /
    • pp.219-224
    • /
    • 1988
  • A decentralised computational procedure is proposed for the optimal feedback gain matrix of large-scale discrete-time systems with time-delays. The constant feedback gain matrix is computed from the optimal state and input trajectries obtained hierarchically by the interaction prediction method. All the calculation in this approach are done off-line. The resulting gains are optimal for all the initial conditions. The interaction prediction method is applied to time-delay large-scale systems with general structures by extending the dimensions of coupling matices. A numerical exampie illustrates the algorithm.

  • PDF

Pat Metheny의 작품 "Question & Answer“의 화성분석 (A Study Harmony on “Question & Answer” of Pat Metheny)

  • 김형준;김대승
    • 한국산학기술학회:학술대회논문집
    • /
    • 한국산학기술학회 2010년도 춘계학술발표논문집 2부
    • /
    • pp.755-758
    • /
    • 2010
  • 본 논문에서는 현재 Jazz에서 사용되어지는 화성기법을 Pat Metheny의 작품인 “Question & Answer”를 통해서 알아보았다. D Minor Pentatonic Scale이 선율에 주로 사용된 본 작품은 Intro부분에서는 Quater Voicing이 사용되었다. A 부분에서는 Line Cliche와 D Minor Scale과 D Harmonic Minor Scale의 Diatonic Chord를 사용하였지만 A Aeolian Mode적인 기법이 A부분 셋 번째 단에서 사용되어 Modal적인 분위기도 연출 하였으며 B부분에서는 John Coltrane이 자주 사용하였던 3 Tonic 기법이 사용되면서 동질의 화성이 일정간격으로 움직이는 Constant Structure기법도 사용되었다.

  • PDF